Apparatus for screening fish from streams of water



J. D. TOFT June 11, 1946.

APPARATUS FOR SCREENING FI SH FROM A STREAM OF WATER Filed Aug. 21, 19452 Sheets-Sheet 1 Inventor 42f: D

J. D. TOFT June 11, 1946.

APPARATUS FOR SCREENING FISH FROM A STREAM OF WATER Filed Aug. 21, 19452 Sheets-Sheet. 2

Patented June 11, 1946 APPARATUS FOR SCREENING FISH FROM STREAMS OFWATER John D. Toft, South Portland, Maine Original application October7, 1943, Serial No.

Divided and this application August 21, 1945, Serial No. 611,800

3 Claims. 1

This application is a division of my prior application Serial No.505,397, filed October 7, 1943 (now Patent No. 2,396,305, dated March12, 1946), and is directed to the novel fish and water separating screenand associated elements which play an important part in the hydraulicfish unloading apparatus and in the removal of the scales from the fish,unloaded from a vessel by the apparatus claimed in that application.

The primary object of the invention of the present application is toprovide an apparatus for separating fish from a flowing stream of water,and which also removes the scales from fish, such as herring, at acannery, prior to the usual processing operations, and simultaneouslywith the unloading of the fish from the vessel which brings them to thecannery from the fishing areas. A further object of the invention is toprovide means for separating the fish, without injury or damage to theirbodies, from a stream of water of large volume, in which the fish areflowing, and by which they are conveyed from the vessel to a point ofdischarge in the cannery.

Another object is to provide a fish and water separating screen havingimproved structural characteristics which enable it to handle fisheffectively and without damage.

A further object is to provide a screen over which the fish may slidewithout damage while large volumes of water flow over their surfaces andthrough the screen, to separate the fish from the stream and to wash thescales from their bodies and to remove them to a point of disposal.

Other and further objects and advantages of the invention will beapparent from a consideration of my parent application above identified,and from a consideration of the illustrative embodiment of the inventionshown somewhat diagrammatically in the accompanying drawings anddescribed below.

In the drawings,

Figure 1 is an end elevation, partly in section, showing, somewhatdiagrammatically, an apparatus in accordance with the invention.

Figure 2 is a similar side elevation, taken from the left of Figure 1.

Figure 3 is a vertical section of a suitable pump which may be employedin the combination of the invention.

Figures 4 and 5 are, respectively, a side elevation and a sectional planof the impeller used in this type of pump, and

Figure 6 is an elevation of a suitable screen for separating the fishand water.

The apparatus of the invention is shown in the accompanying drawings inassociation with a clock In of a fish cannery or other building, aportion of which is indicated at l I. The manner in which the variousparts are positioned with respect to the dock and cannery building ispurely diagrammatic, and the invention is, in no sense,

limited to the arrangement shown.

A relatively large capacity, low pressure centrifugal pump 15 may besupported upon a platform l6, suspended by supporting means I 7 from thedock Ill, or upon a platform supported by the fioor of the sea.Preferably, the pump is positioned below the water level at normal lowtide, the water level being indicated by the dot and dash lines inFigures 1 and 2. The pump may be driven by an electric motor l8 througha shaft i9 or by any equivalent means. The pump inlet 20 is connectedthrough an elbow 2| to a horizontally extending conduit 22 of relativelylarge size, such as a 10 or 12 inch pipe. This conduit terminates at itsremote end 23 in a downturned section 24, having an upwardly openingcheck valve 25 therein. An adjustable gate valve 26, positioned behindthe check valve may be controlled by a vertically extending, rotatableshaft 28 having a hand wheel 21 on its upper end. Since such valves arewell known in the art, it is unnecessary to describe their details ofconstruction, and the representation thereof in the accompanyingdrawings is purely diagrammatic.

Between the valve 26 and the pump l5, and at a point spaced asubstantial distance from the pump, there is a branch conduit 30,connected to the conduit 22 by a T-joint 3|. A standpipe 33, connectedto the upper end of the branch pipe 39 and supported in any suitablemanner upon the dock Ill, carries one end of a large flexible suctionhose 34. Preferably, the pipe 30 and the hose 34 are of smaller diameterthan the pipe 22, for instance, in the neighborhood of 8 or 10 inches,respectively, if a 10 or 12 inch pipe is at 22 used on the inlet side ofthe pump.

At some suitable point in the conduit 30 between the standpipe 33 andthe pipe 22, there is an adjustable gate valve 35, adapted to becontrolled by a hand wheel 36, through a rotatable shaft 3'l or thelike.

A Second branch pipe of relatively small diameter leading from a sourceof water under pressure may be connected to the pipe 22 and controlledby a valve 4| for the introduction of water into the system to prime thepump I5 at the commencement of an operation, if priming is necessary.

The flexible suction pipe 34 is of substantial length and, as shown inFigure 1, its free end 38 is adapted to be lowered into the hold 55 of afishing vessel 46, tied to the dock H3.

Means are provided for adding substantial volumes of water to the fishin the hold of the vessel. For this purpose, one or more hoses 41,connected to a source of water under pressure by a valve 48 may beemployed, or a seacock 49 in the hull of the vessel may be used, thelatter being controlled by any appropriate means, such as a hand wheeland a shaft 5!.

The discharge 55 of the pump 15 is connected through an elbow 56 to avertically extending pipe 5! of such length that its upper end 58 ispreferably located on the second story of the packing house or canneryEl. At this point, means for separating the fish from the water areprovided. Since the volume of water and fish delivered by the pump i5 isquite substantial, the velocity of the upwardly flowing stream in thepipe 51 is high, and it has been found to be of vital importance toreduce the speed of movement of fish before they are discharged upon theseparating means, in order to prevent mutilation of the fish. In theembodiment illustrated in the accompanying drawings, the pipe 5'! at itsupper end supports an angularly disposed pipe section 60 of enlargeddiameter, such as 12 or 14 inches, if the pipe 5'? is of or 12 inchdiameter. When the stream of water and fish enter this enlarged terminalsection, their velocity is reduced to the desired extent, and they flowquite gently upon the separating means positioned adjacent thereto.

The screen which serves to separate the fish from the flowing stream ofwater preferably comprises a frame M of rectangular form supported in arearwardly inclined position, facing the discharge pipe. A plurality ofhorizontal bars 62, spaced a substantial distance apart and secured attheir ends in the frame 6!, carry a great plurality of relatively smallrods 63, welded to the front face thereof, in closely spaced relationand disposed in vertical planes. In the preferred embodiment of theinvention, the rods or bars 63 are smooth, round. welding electrode rodsof substantially three-sixteenths inch diameter, spaced apart a distanceof substantially three-sixteenths of an inch. Rods of this type areadmirably suited for the screen, since they have sufficient strength,present a smooth surface to the fish, are not corroded by sea water, andmay be easily welded to the supporting bars.

It has been found that conventional screens are entirely unsuited forthe work involved in separating fish from a flowing stream of sea water,since the rough surfaces of reticulated or expanded metal screens damagethe fish thrown against them, and small fish and foreign bodies in thestream tend to clog the openings thereof. With a screen of the typedescribed herein, however, the elongated slots of narrow width permitthe passage of water and discard small fish or trash, with the resultthat the screen is substantially completely non-clogging. Moreover, thesmooth, vertically extending, parallel bars present an ideal slidingsurface for the fish thrown thereagainst by the streams of water.

Behind the screen there is positioned a sluiceway or chute 65 for thewater which passes through the screen, to convey the water to a point ofdischarge, such as the end of the dock. In front of the screen means areprovided for conveying the fish to storage or to a processing station.Although any form of conveyor may be used, a sluiceway 66 has been foundsatisfactory. The fish and the water which does not pass through thescreen fiow downwardly through the sluiceway 66 to a transverselyarranged chute or trough 6'! which may extend along and above aplurality of storage tanks, into which the fish may be selectivelydischarged by the use of suitable gates and the like.

The use of a pump of the type shown in Figures 3, 4 and 5, is ofconsiderable importance in the present invention, since such a pump iseffective to convey the fish, without mutilating or damw aging them asthey pass through the impeller chamber. Although pumps of this type arewell known, their structure will be briefiy described, since their usein the combination disclosed herein is thought to be entirely novel. Thepump comprises a large volute casing iii. having an inlet 28, connectedas previously described to an elbow 25 or the like. Within the casing isan impeller H' having an upper imperforate head l2 connected to themotor shaft l8 and a lower head 4.3 having a large opening I4 thereinaligned with the inlet 29. The heads are interconnected by and are castintegrally with vanes 75, 16, having large, relativel unrestricteddischarge passages ll, 18 therebetween. It will be noted that theleading ends of the vanes are smooth, rounded and blunt, and that thetrailing ends are rearwardly inclined and taper to a thin edge, It willbe appreciated that there are substantially no surfaces which canmutilate the fish, since the fish flow axially into the impeller betweenthe blades and laterally through the spaces 11, 78, into the largevolute casing 19, from which they are conveyed by the flowing streamthrough the pipe 51.

It is thought that the operation of the apparatus of the presentinvention and the method of unloading fish from a vessel will beapparent from a consideration of the foregoing description, For the sakeof clarity, however, the procedure will be briefiy outlined.

When a vessel with a cargo of fish, such as herring, has arrived at thedock, the pump I5 is started, with the valve 28 open and the valve 35closed. If necessary, the pump and the pipe 22 are filled with water forpriming purposes by opening the valve ii. If the pump and the pipe 22are submerged in the sea water, as preferred, priming is unnecessary,since the system is normally filled with water, but at extremely lowtides or because of other low water conditions, it is sometimesnecessary to prime the pump. Of course, when priming has been completed,the valve 4| is closed.

With the valves 26 and 3-5 positioned as described above, a solid streamof water will flow through the check valve 25, the conduit 22, the pumpl5 and the discharge pipe 51, Before the valves are readjusted, asubstantial volume of water is introduced into the fish in the hold ofthe ship, either by opening the seacock 49 or by the use of the hoses llor both. The hose 4'! may be a conventional fire hose, equipped with asuitable nozzle to assist in washing down the fish from the sides andcorners of the hold to the suction pipe, particularly during the laststages of the unloading operation.

When a sufiicient body of water has been added to substantially immersethe fish and to displace any air that might otherwise be present in thespaces between thefish, the valve 35 is gradually opened and the valve26 gradually partially closed. This results in a suction in the line 30and the suction hose 34, with the result that the fish and the water inwhich they are immersed start to flow through the hose 34 and the pipe30 to the T connection 3 I, at which point the fish join the stream ofwater flowing through the pipe 22 to the pump I5. The valves are furtheradjusted, to increase the rate of flow of the fish, while continuing theintroduction of additional water into the stream through the conduit 22under the control of valve 26. By properly adjusting these valves, asthe operation continues, an extremely accurate proportioning or blendingof fish and water fiowing through the pipe may be effected, to the endthat the fish are dispersed. to the desired degree in the stream ofwater acting as a carrier. This dispersion of the fish in the water isimportant in preventing damage to the fish as they fiow through thepipes and the pump. If the fish were closely packed in the flowingstream, they would force each other into contact with the pipe walls andinto engagement with the impeller blades and the pump casing walls. Byproviding a relatively large body of free water around the fish, thefish are able to flow freely through the passageways, substantially outof contact with the metallic surfaces thereof, Thus, the proportioningof the water and fish in the flowing stream is of paramount importancein practicing the method of the present invention.

Although a pump of the type described above is substantiallynon-clogging, a concentrated stream of fish introduced into such a pump,would cause damage to the fish b the impeller, but when they aredispersed in a stream of water, to a controlled degree, in accordancewith the present invention, they pass freely through the pump, withoutdamage.

The fish in the stream of water flow upwardly through the pipe 51 fromthe volute casing of the pump, under the hydrostatic head produced bythe centrifugal forces set up by the impeller.

The flow of the stream is sufiiciently rapid to maintain the fish in thedesired dispersed condition. At the upper end of the discharge pipe, thestream enters the enlarged section 60, where its speed of movement isvery substantially reduced so that, when the fish and water aredischarged against the bars 63 of the screen, the fish are not damaged.From this point, the fish flow through the sluiceways, preferably tostorage tanks containing a highly concentrated solution of refrigeratedbrine. From these tanks the fish may be transferred as desired to theusual flaking tanks.

It has been found in actual practice, with the use of the apparatus ofthe present invention, that the fish moving through the conduits indispersed condition in large volumes of water, and through the pump, andthen separated from the stream by the screen 63 lose substantially allof their scales, without damage to the fish. The fish slide down thescreen relatively slowly, as the large volumes of water fiow over theirsurfaces and through the space between the bars 63. The force of theflowing stream holds the fish against the bars with considerable force,but, because of the smooth, rounded surfaces of the bars, the fish arenot damaged. The soaking and agitation of the fish in the water in theconduits, prior to their delivery to the screen tend to loosen thescales and to remove some of them from the skin of the fish. When thefish are discharged against the screen and their movement thus arrested,the Water of the stream, pouring over their surfaces removessubstantially all of the scales and carries them through the slotsbetween bars 63. The scales of such fish as herring are small and arenot particularly firmly attached, so that the soaking of the fish andthe flowing and agitation of the fish in large volumes of water throughthe conduits, through the pump and against the screen tend to dislodgethe scales, which scales flow with the stream through the screen, fordisposal. The scales are so small that they readily pass through theslots, leaving the fish in substantially completely scaled condition, toslide down the sluiceway and chutes to the brine tanks. The fish aretransferred from the refrigerated brine in these tanks to the usualflaking tanks, where any scales not previously removed are deposited.

As illustrating the usual and unexpected fish scaling abilities of theapparatus of the present invention, it may be pointed out that, withconventional methods of unloading fish by hoists and the like, theflaking tanks collect two feet or more of scales in a. predeterminedtime, while the same tanks collect less than two inches of scales in thesame length of time, when the hydraulic fish handling system of thepresent invention is employed. This probably results from the fact that,with the old methods, the fish were handled in batches, withsubstantially no agitation in large volumes of water so that the scaleswere not soaked and removed prior to their delivery to the flakingtanks.

Although the invention has been described with considerableparticularity, by reference to the embodiment shown in the drawings, itmust be understood that it is not limited to the details of constructionshown and described, but covers all modifications coming within thescope of the appended claims and their equivalents.

I claim:

1. An apparatus for screening fish from a flowing stream of water,comprising a. screen inclined from a vertical plane and having a frontface consisting of a plurality of straight, spaced parallel barsinclined upwardly and rearwardly from the lower to the upper edge of thescreen, and a conduit for delivering the fish and water to the screen,said conduit terminating in an open discharge end adjacent to, spacedfrom and located in front of the screen and arranged to discharge thestream and the fish upwardly in substantially the same inclineddirection as the screen, whereby the stream passes through the screenand the fish slide down along said bars without mutilation.

2. An apparatus for screening fish from a flowing stream of water,comprising a screen inclined from a vertical plane and having a frontface consisting of a plurality of straight, spaced parallel barsinclined upwardly and rearwardly from the lower to the upper edge of thescreen, and a conduit for delivering the fish and water to the screen,said conduit having a terminal portion substantially parallel to thescreen and having an open discharge end adjacent to, spaced from andlocated in front of the screen and arranged to discharge the stream andthe fish upwardl in a direction substantially parallel to the screen,whereby the stream passes through the screen under the influence ofgravity and the fish slide down alon said bars without mutilation.

3. An apparatus for screening fish from a flowing stream of water,comprising a screen inclined from a vertical plane and having a frontface consisting of a plurality of straight, spaced parallel barsinclined upwardly and rearwardly from the lower to the upper edge of thescreen, a.c0nduit for delivering the fish and water to the screen, saidconduit terminating in an open discharge end adjacent .to, spaced fromand located in front of the screen and arranged to discharge the streamand the fish upwardly in substantially the same inclined direction asthe screen, whereby the stream passes through the screen and thefishslide down along said bars without mutilation, means behindthescreen for collecting the water passing therethrough, a, disposalconduit leading from said collecting means, and means in front of andbelow the screen for continuously conveying the fish to storage or thelike.

JOHN D. TOFT.

